In 2003, and again last year, lone wild tigresses in the Russian Far East wandered into local villages, seemingly unfazed by their surroundings. Both cats showed abnormal neurologic signs, and researchers collected samples to investigate their cases. Last year, the trespasser was Galia, a female tiger that WCS researchers had studied for eight years in the Sikhote-Alin Biosphere Reserve. Galia appeared gaunt and was searching for dogs as an easy meal. After several capture attempts failed, local police shot her.

Working at WCS’s Wildlife Health Center at the Bronx Zoo, Russian health experts and WCS pathologists recently confirmed a diagnosis in the wandering big cats: distemper. The team is now formulating health measures to counter this latest threat. Recently, they presented their findings at a symposium on wildlife diseases held in the city of Ussurisk. The first of its kind in Russia, the symposium underscores growing recognition of the important role that health sciences play in wildlife conservation.

“This exchange provides a foundation for elucidating potential disease threats to tigers in the Russian Far East,” said Irina Korotkova of the Primorskaya Agricultural Academy. “Understanding the role of distemper in our wild Amur tiger population is vitally important.”

Distemper is a measles-like virus found worldwide in domestic dogs. It also affects wild species such as lynx and bobcats in Canada, Baikal seals in Russia, lions in the Serengeti ecosystem in Africa, and raccoons and black-footed ferrets in the U.S. Veterinarians are able to control canine distemper in domestic dogs through vaccination. In Africa, massive vaccination campaigns of dogs in villages surrounding the Serengeti appear to have reduced the virus's impact on lions.

"With all the threats facing Siberian tigers from poaching and habitat loss, relatively little research has been done on diseases that may afflict tigers,” said Dale Miquelle, WCS Director of Russia Programs. “There are no records of tigers entering villages and behaving so abnormally before 2000, so this appears to be a new development and new threat. Understanding whether disease is a major source of mortality for Siberian tigers is crucial for future conservation efforts.”

Several other sightings of tigers entering villages or stalling traffic on major roadways—behavior possibly indicative of distemper—have been reported in recent years.

Dr. Denise McAloose, WCS’s Chief Pathologist and leader of the investigation, praised the international teamwork. “Without our Russian associates there on the spot, knowing what samples to collect and how to preserve these specimens, samples would never have made it to our lab, and the cause of death would remain unknown,” she said.

WCS is working with staff from the Primorskaya Agriculture Academy and other partners to establish a wildlife lab in Ussurisk to facilitate local diagnostic testing. It is expected to take several years until the lab is adequately funded and fully functional.

McAloose added: “Until then, there’s still much to do, including identifying the source of the disease.”

It is still uncertain how tigers may have contracted the disease and whether it originated in another wild animal species or domestic dogs, both of which can act as reservoirs for the infection.

Latest reports suggest that fewer than 3,500 tigers remain in the wild; 1,000 are breeding females.